﻿206 
  REPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  

  

  Following 
  is 
  a 
  table 
  showing 
  the 
  approximate 
  time 
  required 
  for 
  cod 
  

   eggs 
  to 
  hatch, 
  with 
  the 
  water 
  at 
  the 
  stated 
  mean 
  temperatures 
  : 
  

  

  Mean 
  water 
  tem- 
  

   perature. 
  

  

  31° 
  F 
  

   32° 
  F 
  

   33° 
  F 
  

   34° 
  K 
  

   35° 
  F 
  

   36° 
  F 
  

  

  Ifo. 
  of 
  

   (lays. 
  

  

  50 
  

   40 
  

   35 
  

   31 
  

   28 
  

   25 
  

  

  Mean 
  water 
  tem- 
  

   perature. 
  

  

  43° 
  F 
  

   44° 
  F 
  

   450 
  F 
  

   46° 
  F 
  

   47° 
  F 
  

  

  No. 
  of 
  

   days. 
  

  

  14 
  

   13 
  

   12 
  

   11 
  

   10 
  or 
  11 
  

  

  Moderately 
  clear 
  water 
  is 
  essential 
  to 
  the 
  healthy 
  development 
  of 
  

   the 
  fry. 
  If 
  much 
  sediment 
  is 
  present 
  it 
  collects 
  on 
  the 
  eggs 
  and 
  acts 
  

   very 
  injuriously, 
  often 
  killing 
  them. 
  Sometimes 
  eggs 
  become 
  so 
  coated 
  

   with 
  sediment 
  that 
  the 
  fry 
  appear 
  to 
  be 
  unable 
  to 
  burst 
  the 
  shell; 
  

   some 
  lots 
  of 
  eggs 
  thus 
  affected 
  have 
  been 
  known 
  to 
  retain 
  fry 
  fully 
  two 
  

   weeks 
  beyond 
  the 
  normal 
  period 
  of 
  incubation. 
  

  

  With 
  eggs 
  carefully 
  taken 
  and 
  fertilized, 
  and 
  clear 
  water 
  of 
  a 
  

   temperature 
  from 
  41° 
  to 
  47° 
  F., 
  it 
  is 
  iiossible 
  to 
  hatch 
  from 
  70 
  to 
  85 
  

   per 
  cent 
  of 
  the 
  eggs, 
  but 
  when 
  the 
  temperature 
  gets 
  below 
  38° 
  the 
  

   percentage 
  of 
  fry 
  hatched 
  is 
  only 
  from 
  25 
  to 
  50, 
  and 
  the 
  average 
  for 
  the 
  

   season 
  is 
  thus 
  greatly 
  reduced. 
  The 
  number 
  of 
  fry 
  hatched 
  is 
  deter- 
  

   mined 
  by 
  deducting 
  the 
  losses 
  shown 
  on 
  the 
  hatching-cards 
  from 
  the 
  

   number 
  of 
  eggs 
  originally 
  in 
  the 
  box. 
  One 
  liquid 
  ounce 
  is 
  estimated 
  

   to 
  contain 
  10,524 
  eggs. 
  

  

  CLEANING 
  THE 
  EGGS. 
  

  

  Owing 
  to 
  the 
  accumulation 
  of 
  sediment 
  and 
  other 
  foreign 
  matters 
  in 
  

   the 
  hatching-boxes, 
  it 
  is 
  necessary 
  to 
  clean 
  the 
  eggs 
  daily, 
  running 
  the 
  

   sound 
  eggs 
  from 
  one 
  box 
  to 
  another 
  through 
  a 
  slot, 
  the 
  dead 
  eggs 
  

   being 
  lelt 
  behind. 
  The 
  slots 
  in 
  the 
  partitions 
  dividing 
  the 
  hatching 
  

   compartments 
  correspond 
  with 
  similar 
  slots 
  in 
  the 
  boxes 
  ; 
  they 
  are 
  3 
  

   to 
  3J 
  inches 
  long 
  and 
  1^ 
  inches 
  deep, 
  and 
  are 
  placed 
  3 
  inches 
  from 
  the 
  

   front 
  of 
  the 
  compartments. 
  To 
  begin 
  the 
  cleaning 
  of 
  a 
  given 
  row 
  of 
  

   boxes, 
  a 
  glass 
  slip 
  is 
  fitted 
  into 
  the 
  slot 
  between 
  the 
  second 
  and 
  third 
  

   boxes, 
  the 
  first 
  box 
  being 
  left 
  empty 
  for 
  the 
  purpose 
  of 
  receiving 
  the 
  

   cleaned 
  eggs 
  from 
  the 
  second 
  box. 
  A 
  wooden 
  plug 
  is 
  then 
  put 
  in 
  the 
  

   current 
  hole 
  at 
  the 
  back 
  of 
  the 
  second 
  box, 
  and 
  the 
  siphon 
  cap 
  is 
  

   removed 
  from 
  the 
  waste 
  pipe; 
  this 
  allows 
  the 
  box 
  to 
  fill 
  with 
  water, 
  

   and 
  the 
  eggs, 
  undisturbed 
  by 
  the 
  current, 
  rise 
  to 
  the 
  surface. 
  The 
  

   water 
  is 
  allowed 
  to 
  enter 
  the 
  first 
  box 
  and 
  to 
  gradually 
  fill 
  it 
  to 
  the 
  

   level 
  of 
  the 
  waste 
  pipe, 
  and 
  is 
  then 
  turned 
  off. 
  A 
  plug 
  is 
  next 
  put 
  in 
  

   the 
  waste-pipe 
  of 
  the 
  box 
  containing 
  the 
  eggs; 
  the 
  water 
  rises 
  till 
  it 
  

   reaches 
  the 
  slot, 
  and 
  then 
  runs 
  over 
  into 
  the 
  first 
  box, 
  carrying 
  the 
  good 
  

   eggs 
  with 
  it, 
  while 
  the 
  dead 
  eggs 
  remain 
  in 
  the 
  box. 
  The 
  regular 
  water 
  

   circulation 
  is 
  then 
  established 
  in 
  the 
  first 
  box. 
  

  

  The 
  inner 
  box 
  from 
  which 
  the 
  good 
  eggs 
  have 
  been 
  removed 
  is 
  taken 
  

   out 
  and 
  the 
  remaining 
  eggs 
  are 
  washed 
  into 
  one 
  end 
  and 
  poured 
  into 
  

  

  